Spark plug



Patented July 21, 1936 UNITED STATES PATENT OFFICE 2 Claims.

. the insulating sleeve from overheating while providing a sufliciently high temperature but not an excessively high temperature, at and in the neighborhood of the spark gap, to controllably relieve the insulating sleeve from the burden of conducting heat from the electrode that projects from its inner end, and to efllciently use the heat conductivity of the water jacket of the cylinder head for dissipating heat from the spark" plug.

Other objects of the invention will appear from the following description at the end of which the invention will be claimed.

Generally stated, the invention consists of a spark plug including a body internally provided with a shoulder and externally provided with a shoulder and externally provided with a thread arranged in proximity with each other for good heat transfer, to the water jacket, said body having a single annular opening at its inner end, and including a shouldered refractory sleeve having an electrode projecting from its inner end; there being provided a second electrode consisting of a gasket seated between said shoulders in proximity with the water jacket and of a ring in proximity with the first mentioned electrode to provide a spark gap and of arms extending from the ring to the gasket and which carry current and also conduct heat from the spark gap to the body thereby lessening the burden of heat conduction imposed on the refractory sleeve to an extent controlled by the size of the arms.

The invention also comprises the improvements to be presently described and finally claimed.

In the following description reference will be made to the accompanying drawing forming part hereof and in whic Figure 1 is a view principally in central section of a spark plug embodying features of the invention; and

Figure 2 is a perspective view of the electrode which assists the sleeve of refractory material in conducting heat from the neighborhood of the spark gap to the body near the water jacket.

In the drawing, i is the body of the plug, and it is provided with a single annular opening 2 at its inner end. Internally the body is provided with a shoulder 3 and externally the body is provided with a thread 4. The thread and the shoulder are arranged in heat conducting proximity with each other and with the water of the jacket 5 oi the cylinder head. 6 is a'sleeve of refractory heat conducting and electrically insulating material and it is shouldered as at l. The sleeve 6 is provided at its inner end with a projecting electrode 8. The other electrode structure comprises a ring 9 in proximity with the elec- 5 trode 8 to provide a spark gap, and a gasket l0 seated between the shoulders 3 and 'l, and arms II of which two are shown, but the number and Size of the arms H are determined by the quantity of heat they are required to conduct from 10 the region of the spark gap to the body and water jacket in order to permit the sleeve 6 to conduct a suillcient quantity of heat to keep the electrode 8 below a temperature that would injure it and at a sufllciently high temperature to insure the presence of a good spark by preventing the deposition of carbon on the electrode.

The hottest part of the device is in a zone surrounding the parts 8 and 9 and the sleeve 6 is very hot, probably hotter than the plug. It is an important feature of the invention that heat be transferred from that zone and dissipated. The coolest region is in the neighborhood of the gasket Hi. It is the function of the arms to conduct heat from the zone to the cooler region of the device and for that purpose'two things are desirable: first, that good heat conducting contact be made between the arms H and the body and this the gasket accomplishes; and second, that the arms be not unduly heated between the zone and region referred to. This is accomplished by keeping the arms out of contact with the sleeve 6, and it is well to keep the arms out of substantial contact with the body I. The line contact at the inner rim of the opening 2 is negligible.

It will be obvious to those skilled in the art to which the invention relates that modifications may be made in details of construction and in matters of mere form without departing from 0 the spirit of the invention which is not limited to such matters or otherwise than as the prior art and the appended claims may require.

I claim:

1. A spark plug having an electrode structure 45.

comprising at its inner end a gasket and at its outer end a ring and current carrying and heat conducting arms connecting the gasket and the ring, in combination with a refractory sleeve having at its inner end a projecting electrode providing with the ring a spark gap, and with a body externally threaded for insertion through the water jacket of a cylinder head, said sleeve and body having shoulders between which the asket is held in proximity with the thread on y 1, 936. G. BABCOCK 2,048,482

TELEPHONE ADAPTER Filed May 21, 1932 2 Sheets-Sheet 1 

